1. Technical Field
The present invention relates to stators for rotating electric machines that are used in, for example, motor vehicles as electric motors and electric generators.
2. Description of Related Art
There are known stators for rotating electric machines which include an annular stator core and a three-phase stator coil. The stator core has a plurality of slots arranged in its circumferential direction. The stator coil is comprised of a plurality of phase windings. The phase windings are mounted on the stator core so as to be partially received in the slots of the stator core. In addition, those parts of the phase windings which are located outside the slots of the stator core together make up a pair of coil ends of the stator coil which respectively protrude from an opposite pair of axial end faces of the stator core.
Moreover, the phase windings of the stator coil may be star-connected to define a neutral point therebetween. In this case, it is necessary to connect ends of the phase windings at the neutral point by, for example, welding. To this end, a plurality of long bridging wires may be employed; the bridging wires extend on one of the coil ends of the stator coil so as to bridge the phase windings. Alternatively, as disclosed in, for example, Japanese Patent Application Publication No. JP2004120905A, a busbar may be employed; the busbar is arranged on one of the coil ends of the stator coil so as to have the ends of phase windings connected thereto.
However, during operation of the rotating electric machine, the stator is generally subjected to both circumferential vibration caused by rotation of a rotor of the machine and radial vibration caused by imbalance of the rotor. Consequently, in the case of employing the long bridging wires, the influence of the vibrations on the stator coil will be increased due to the long-distance extending of the bridging wires on the coil end of the stator coil. On the other hand, in the case of employing the busbar, the influence of the vibrations on the stator coil will also be increased by the weight of the busbar.